Cellular Helmet Liner Design through Bio-inspired Structures and Topology Optimization of Compliant Mechanism Lattices

The continuous development of sport technologies constantly demands advancements in protective headgear to reduce the risk of head injuries. This article introduces new cellular helmet liner designs through two approaches. The first approach is the study of energy-absorbing biological materials. The second approach is the study of lattices comprised of force-diverting compliant mechanisms. On the one hand, bio-inspired liners are generated through the study of biological, hierarchical materials. An emphasis is given on structures in nature that serve similar concussion-reducing functions as a helmet liner. Inspiration is drawn from organic and skeletal structures. On the other hand, compliant mechanism lattice (CML)-based liners use topology optimization to synthesize rubber cellular unit cells with effective positive and negative Poisson's ratios. Three lattices are designed using different cellular unit cell arrangements, namely, all positive, all negative, and alternating effective Poisson's ratios. The proposed cellular (bio-inspired and CML-based) liners are embedded between two polycarbonate shells, thereby, replacing the traditional expanded polypropylene foam liner used in standard sport helmets. The cellular liners are analyzed through a series of 2D extruded ballistic impact simulations to determine the best performing liner topology and its corresponding rubber hardness. The cellular design with the best performance is compared against an expanded polypropylene foam liner in a 3D simulation to appraise its protection capabilities and verify that the 2D extruded design simulations scale to an effective 3D design

The Pros and Cons of Carbon Taxes and Cap-and-Trade Systems

As part of Canada's effort to meet its commitment to the 2015 Paris climate accord, the provinces must establish their own carbon pricing policies or the federal government will impose a policy on them. When choosing among the various policies, provincial governments should first determine how much a particular policy will negatively affect economic competitiveness in their jurisdictions. When the negative impacts are judged to be low, a carbon tax on each tonne of greenhouse gas emissions (GHG) is the preferred choice. A cap-and-trade policy allocating tradable permits under a market price, or a hybrid combination of carbon tax and cap-and-trade, is best when the negative impacts could be high. These three policies can all satisfactorily achieve emissions reductions. However, other variables must be taken into consideration, including the provision of price certainty, how strongly each policy promotes innovative research into cleaner technologies, the complexity and costs of set-up, the policy’s salience, or visibility to consumers, and the amount of revenue it can raise. A carbon tax has a major advantage over cap-and-trade and a hybrid version because it allows for carbon price certainty, is less costly to administer and is a substantial source of revenue. However, a cap-and-trade policy offers its own advantages in that emissions allowances can be allocated so as to minimize the policy’s negative effects on competitiveness and prevent emissions leakage. The latter is the term used when companies leave one jurisdiction to operate in another jurisdiction that has either fewer or no rules around carbon pricing. A hybrid policy, also known as output-based pricing, allows for some permits to be allocated freely based on a facility’s or industrial sector’s emissions and output. It also offers more carbon price certainty than a pure cap-and-trade system. Research shows that a hybrid policy almost completely reduces the impacts on competitiveness and emissions leakage. And while a carbon tax is more visible to the public, the advantages of higher visibility are debatable. Such a policy may be favourable because a lower price is required to achieve the same GHG reductions, but it might also be unfavourable because politically it is less palatable. British Columbia has a carbon tax, while Quebec uses a cap-and-trade system. Alberta has a hybrid policy that covers large industrial emitters and a carbon tax for smaller ones. Other provinces remain without a carbon pricing regime, while Ontario’s newly elected Progressive Conservative government is set to dismantle the province’s cap-and-trade policy. Those provinces that wait for the federal government to impose carbon pricing on them can expect to get a hybrid policy much like Alberta’s. For provincial governments wishing to establish their own policies, choosing one that is the right fit involves weighing the advantages and disadvantages of each. Ultimately, a given jurisdiction should examine its own economic and emissions profile in order to make the best choice for achieving the combined goal of reducing GHGs without negatively impinging on industry’s competitiveness

Realigning a Graduate Program

https://fuse.franklin.edu/ss2016/1064/thumbnail.jp

A Selected Surveyo f Ocean Acidifcation\u27s Effect on Coccolithophore and other Marine Ecosystems

With it\u27s rapid rate of generation, the coccolithophore was expected to adapt to the altered pH levels relatively quickly. By analyzing several scientific studies concerning this algae\u27s interaction with various water qualities, the species\u27 response is clarified. These findings are compared to rudimentary data concerning pH levels taken along the coast of Malibu

The Pros and Cons of Carbon Taxes and Cap-and-Trade Systems

As part of Canada's effort to meet its commitment to the 2015 Paris climate accord, the provinces must establish their own carbon pricing policies or the federal government will impose a policy on them. When choosing among the various policies, provincial governments should first determine how much a particular policy will negatively affect economic competitiveness in their jurisdictions. When the negative impacts are judged to be low, a carbon tax on each tonne of greenhouse gas emissions (GHG) is the preferred choice. A cap-and-trade policy allocating tradable permits under a market price, or a hybrid combination of carbon tax and cap-and-trade, is best when the negative impacts could be high. These three policies can all satisfactorily achieve emissions reductions. However, other variables must be taken into consideration, including the provision of price certainty, how strongly each policy promotes innovative research into cleaner technologies, the complexity and costs of set-up, the policy’s salience, or visibility to consumers, and the amount of revenue it can raise. A carbon tax has a major advantage over cap-and-trade and a hybrid version because it allows for carbon price certainty, is less costly to administer and is a substantial source of revenue. However, a cap-and-trade policy offers its own advantages in that emissions allowances can be allocated so as to minimize the policy’s negative effects on competitiveness and prevent emissions leakage. The latter is the term used when companies leave one jurisdiction to operate in another jurisdiction that has either fewer or no rules around carbon pricing. A hybrid policy, also known as output-based pricing, allows for some permits to be allocated freely based on a facility’s or industrial sector’s emissions and output. It also offers more carbon price certainty than a pure cap-and-trade system. Research shows that a hybrid policy almost completely reduces the 1 impacts on competitiveness and emissions leakage. And while a carbon tax is more visible to the public, the advantages of higher visibility are debatable. Such a policy may be favourable because a lower price is required to achieve the same GHG reductions, but it might also be unfavourable because politically it is less palatable. British Columbia has a carbon tax, while Quebec uses a cap-and-trade system. Alberta has a hybrid policy that covers large industrial emitters and a carbon tax for smaller ones. Other provinces remain without a carbon pricing regime, while Ontario’s newly elected Progressive Conservative government is set to dismantle the province’s cap-and-trade policy. Those provinces that wait for the federal government to impose carbon pricing on them can expect to get a hybrid policy much like Alberta’s. For provincial governments wishing to establish their own policies, choosing one that is the right fit involves weighing the advantages and disadvantages of each. Ultimately, a given jurisdiction should examine its own economic and emissions profile in order to make the best choice for achieving the combined goal of reducing GHGs without negatively impinging on industry’s competitiveness

Is Antiretroviral Therapy Cost-Effective in South Africa?

Braithwaite and Tsevat discuss a new study that suggests that antiretroviral treatment is indeed cost-effective

Gas Storage Technology Consortium

The EMS Energy Institute at The Pennsylvania State University (Penn State) has managed the Gas Storage Technology Consortium (GSTC) since its inception in 2003. The GSTC infrastructure provided a means to accomplish industry-driven research and development designed to enhance the operational flexibility and deliverability of the nation's gas storage system, and provide a cost-effective, safe, and reliable supply of natural gas to meet domestic demand. The GSTC received base funding from the U.S. Department of Energy's (DOE) National Energy Technology Laboratory (NETL) Oil & Natural Gas Supply Program. The GSTC base funds were highly leveraged with industry funding for individual projects. Since its inception, the GSTC has engaged 67 members. The GSTC membership base was diverse, coming from 19 states, the District of Columbia, and Canada. The membership was comprised of natural gas storage field operators, service companies, industry consultants, industry trade organizations, and academia. The GSTC organized and hosted a total of 18 meetings since 2003. Of these, 8 meetings were held to review, discuss, and select proposals submitted for funding consideration. The GSTC reviewed a total of 75 proposals and committed co-funding to support 31 industry-driven projects. The GSTC committed co-funding to 41.3% of the proposals that it received and reviewed. The 31 projects had a total project value of $6,203,071 of which the GSTC committed$3,205,978 in co-funding. The committed GSTC project funding represented an average program cost share of 51.7%. Project applicants provided an average program cost share of 48.3%. In addition to the GSTC co-funding, the consortium provided the domestic natural gas storage industry with a technology transfer and outreach infrastructure. The technology transfer and outreach were conducted by having project mentoring teams and a GSTC website, and by working closely with the Pipeline Research Council International (PRCI) to jointly host technology transfer meetings and occasional field excursions. A total of 15 technology transfer/strategic planning workshops were held

Does Obesity Cause Thyroid Cancer? A Mendelian Randomization Study

Background: The incidence of thyroid cancer is rising, and relatively little is known about modifiable risk factors for the condition. Observational studies have suggested a link between adiposity and thyroid cancer; however, these are subject to confounding and reverse causality. Here, we used data from the UK Biobank and Mendelian randomization approaches to investigate whether adiposity causes benign nodular thyroid disease and differentiated thyroid cancer. Methods: We analyzed data from 379 708 unrelated participants of European ancestry in the UK Biobank and identified 1812 participants with benign nodular thyroid disease and 425 with differentiated thyroid carcinoma. We tested observational associations with measures of adiposity and type 2 diabetes mellitus. One and 2-sample Mendelian randomization approaches were used to investigate causal relationships. Results: Observationally, there were positive associations between higher body mass index (odds ratio [OR], 1.15; 95% confidence interval [CI], 1.08-1.22), higher waist-hip ratio (OR, 1.16; 95% CI, 1.09-1.23), and benign nodular thyroid disease, but not thyroid cancer. Mendelian randomization did not support a causal link for obesity with benign nodular thyroid disease or thyroid cancer, although it did provide some evidence that individuals in the highest quartile for genetic liability of type 2 diabetes had higher odds of thyroid cancer than those in the lowest quartile (OR, 1.45; CI, 1.11-1.90). Conclusions: Contrary to the findings of observational studies, our results do not confirm a causal role for obesity in benign nodular thyroid disease or thyroid cancer. They do, however, suggest a link between type 2 diabetes and thyroid cancer.This article is freely available via Open Access. Click on the Publisher URL to access it via the publisher's site.WT_/Wellcome Trust/United Kingdompublished version, accepted version (12 month embargo), submitted versio

Pressure Gradient Effects on Hypersonic Cavity Flow Heating

The effect of a pressure gradient on the local heating disturbance of rectangular cavities tested at hypersonic freestream conditions has been globally assessed using the two-color phosphor thermography method. These experiments were conducted in the Langley 31-Inch Mach 10 Tunnel and were initiated in support of the Space Shuttle Return-To-Flight Program. Two blunted-nose test surface geometries were developed, including an expansion plate test surface with nearly constant negative pressure gradient and a flat plate surface with nearly zero pressure gradient. The test surface designs and flow characterizations were performed using two-dimensional laminar computational methods, while the experimental boundary layer state conditions were inferred using the measured heating distributions. Three-dimensional computational predictions of the entire model geometry were used as a check on the design process. Both open-flow and closed-flow cavities were tested on each test surface. The cavity design parameters and the test condition matrix were established using the computational predictions. Preliminary conclusions based on an analysis of only the cavity centerline data indicate that the presence of the pressure gradient did not alter the open cavity heating for laminar-entry/laminar-exit flows, but did raise the average floor heating for closed cavities. The results of these risk-reduction studies will be used to formulate a heating assessment of potential damage scenarios occurring during future Space Shuttle flights